So basically, in the short scene from the trailer we see Littlefinger lunge at Jon Snow and Jon attacking back. But more important than the fight itself is the setting, which appears to be in the crypts of Winterfell. In particular, it looks as though they're next to the tomb of Eddard Stark's sister Lyanna Stark.

SPOILER ALERT: The rest of this post will go into detail about Jon Snow's parentage, which hasn't been officially revealed on the show yet. Don't read on if you want to remain pure.

So what does that mean? If they really are near Lyanna's tomb, then we can assume that Littlefinger just told Jon about his true parentage... and our favorite bastard did not take it well.

After all, if there's anyone in the Seven Kingdoms who'd have all the dirty deets about Jon, it would for sure be Littlefinger.

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So now everyone is thinking Littlefinger is going to instigate a fight with Jon by telling him his mother is Lyanna Stark. Thinking his father his Ned Stark, Jon will assume Littlefinger is saying he's a product of incest and lash out.

In actuality, though, we know Jon's parents are Lyanna Stark and Rhaegar Targaryen, making him one of the last Targaryens in the world, along with Daenerys. It looks like this will be the scene in which Jon finally stops being Ned Stark's bastard and learns the truth about his heritage.